I think Matej meant Ctrl-Backspace, rather than Alt-Backspace. And now (as of build 757 anyway -- see Bug 592033), Ctrl-Backspace works as expected. :)
I think Matej meant Ctrl-Backspace, rather than Alt-Backspace. And now (as of build 757 anyway -- see Bug 592033), Ctrl-Backspace works as expected. :)